A former Barcelona player, Alexis Sánchez may well already by striking fear into Tuesday’s opposition before a ball is kicked.

There is plenty of talk about the opposition trio of Lionel Messi, Luis Suárez and Neymar (understandably so – they’re the best strikeforce in football) but Arsenal have their own weapons too. Alexis may be struggling for form, but Arsenal’s benefit is that the opposition know how good he is at his best.

“What makes Alexis so dangerous is that he is unpredictable,” superstar midfielder Andres Iniesta said to the Spanish giants’ YouTube channel. “When he dribbles, when he attacks, he is a very strong player.

“He’s got skill and when he has the ball he always creates doubts. In that sense, we have to try to make him feel uncomfortable on the field and try to minimise his strengths.”

If Alexis creates doubts, the Gunners have to capitalise on them, but that will take a level of performance the Chilean hasn’t shown for months.

Iniesta isn’t the only player in awe of his former teammate, as Javier Mascherano told The Independent about the challenge facing the winger poses.

“He is a fighter. He never gives up a single ball for lost,” said the Argentine. “He is always going to give everything. And that is fundamental for any team.

“He delivered in the time he was here. He was very involved. Maybe he just needed the challenge of having a greater part to play in another team… now he has a huge role to play for Arsenal. He is crucial to what they do. He is someone whose aggression and attitude is infectious.”

No matter what his form has been like, it must give Alexis a boost going into the game on Tuesday that he knows the opposition have no doubt what he’s capable of. Barcelona are used to playing huge games against the very finest opponents, but they don’t often come up against one of their own.

Alexis needs to improve on recent form if he is going to influence such a big game but, if he delivers, Arsenal could just have a shot.